In common with the average skimmer of headlines, I don’t know much about the Iran deal or what the consequences will be now that the US has walked away. But you don’t have to be to your chin in international politics to suspect they won’t benefit the world.

I wanted a visual image or metaphor to sum up this situation. And this is what came to mind: Trump stands before a pile of leaking oil containers and as the escaping inflammables spread towards him, he says something like: “That was a very bad deal, the worst deal in history. Obama made that deal and he was rubbish at deals. He doesn’t know deals like I know deals. I am a very good man for the deal.”

Trump then lights a match and flicks the flame towards the incontinent barrels. “That’s what I think of Obama’s deal. My deal is so much better. Iran will sit up and take notice of my deal, and…”

Boom! A very big boom! The biggest and best boom in the history of big booms!

Being the king of deals is part of the Trump mythology, but few of us know if he is truly any good with a deal. Most of us have avoided being in a room with the man, thanks heavens, but we do know that shouldering your way to a property deal isn’t the usual training for painstaking international diplomacy.

It is fair to say that the Iran deal wasn’t perfect, but it had helped keep the peace for a while, and had been drawn up multilaterally by many countries after years of talks.

Sadly, collaborating for the common good is no good if you are Donald Trump, especially if you have assorted neocon nut jobs whispering sour nothings in your ear: “Drop those bombs” “Kill that deal…”

Add to that the unstable volcano of Trump’s vanity and you begin to worry about the world. It’s hard not to believe that Trump’s distrust and hostility towards the Iran deal is all tied in with his animus towards his predecessor. Almost anything Obama did, Trump thinks he can do better; and if he can’t, he’ll just have a tantrum and smash everything in the room.

Trump thinks the Iran deal was a bad deal because he didn’t make it; he sees everything through the lens of self and swears that anything done by anyone else cannot be any good.

It’s the sort of macho, idiotic carry-on you expect from a self-styled business supremo, I guess, but transpose that to the president of the US and it starts to look like that nightmare where an idiot Batman villain has taken over the world; only that is no dream.

Trump’s decision to violate the international agreement that has prevented Iran from obtaining a nuclear bomb just looks like swaggering bluster of a man who knows nothing but still knows better than everyone else.

Many believe a war with Iran is now more likely, and that such a conflict could engulf the Middle East. So perhaps my opening metaphor isn’t too wide of the mark.

We need to maintain diplomatic relations with the US, and for now that involves dealing with the dealer. But all the hand-holding from Mrs Maybe, the big bromance with Macron, the stony-faced “visiting the relatives from hell” meetings with Merkel – all of that comes to nothing with a quixotic man like Trump. If he wants to do something, he’ll do it anyway.

And right now, he’s just dropped a lit match.